genetic adaptation of caenorhabditis elegans (nematoda) to high temperatures
TRANSCRIPT
References and Notes
1. D. H. Copp, E. C. Cameron, B. A. Cheney, A. G. F. Davidson, K. G. Henze, Endocrinol- ogy 70, 638 (1962).
2. P. F. Hirsch, G. F. Gauthier, P. L. Munson, ibid. 73, 244 (1963).
3. P. F. Hirsch, E. F. Voelkel, P. L. Munson, Science 146, 412 (1964).
4. A. Baghdiantz, G. V. Foster, A. Edwards, M. A. Kumar, E. Slack, H. A. Soliman, I. MacIntyre, Nature 203, 1027 (1964).
5. A. Tenenhouse, C. Arnaud, H. Rasmussen, Proc. Nat. Acad. Sci. U.S. 53, 818 (1965).
6. L. G. Raisz, J. Clin. Invest. 44, 106 (1965). 7. A. D. Kenny and C. A. Heiskell, Fed. Proc.
24, 322 (1965). 8. M. A. Aliapoulios, A. Savery, P. L. Munson,
ibid., p. 322. 9. Supported by PHS grant AM 06205 and by
a Burroughs-Wellcome clinical pharmacology award. We thank William Y. W. Au for his invaluable help.
7 September 1965
Genetic Adaptation of Caenorhabditis elegans (Nematoda) to High Temperatures
Abstract. When taken directly from a strain kept for several years at 18?C in the laboratory, Caenorhabditis elegans cannot reproduce indefinitely at temper- atures higher than 22?C. By progressive and very slow increments of the breed- ing temperature, a strain fecund at 24.5?C was obtained.
Caenorhabditis elegans is a species consisting almost entirely of hermaphro- ditic, self-fertilizing individuals (about one male out of 1000 hermaphrodites). Its fecundity is easy to measure when the nematodes are raised individually on a special agar medium (1). At 18?C, the strain Bergerac (2) studied shows an average fecundity of 141 offspring per hermaphrodite.
When an embryo grown at 18?C is transferred to growing conditions at
References and Notes
1. D. H. Copp, E. C. Cameron, B. A. Cheney, A. G. F. Davidson, K. G. Henze, Endocrinol- ogy 70, 638 (1962).
2. P. F. Hirsch, G. F. Gauthier, P. L. Munson, ibid. 73, 244 (1963).
3. P. F. Hirsch, E. F. Voelkel, P. L. Munson, Science 146, 412 (1964).
4. A. Baghdiantz, G. V. Foster, A. Edwards, M. A. Kumar, E. Slack, H. A. Soliman, I. MacIntyre, Nature 203, 1027 (1964).
5. A. Tenenhouse, C. Arnaud, H. Rasmussen, Proc. Nat. Acad. Sci. U.S. 53, 818 (1965).
6. L. G. Raisz, J. Clin. Invest. 44, 106 (1965). 7. A. D. Kenny and C. A. Heiskell, Fed. Proc.
24, 322 (1965). 8. M. A. Aliapoulios, A. Savery, P. L. Munson,
ibid., p. 322. 9. Supported by PHS grant AM 06205 and by
a Burroughs-Wellcome clinical pharmacology award. We thank William Y. W. Au for his invaluable help.
7 September 1965
Genetic Adaptation of Caenorhabditis elegans (Nematoda) to High Temperatures
Abstract. When taken directly from a strain kept for several years at 18?C in the laboratory, Caenorhabditis elegans cannot reproduce indefinitely at temper- atures higher than 22?C. By progressive and very slow increments of the breed- ing temperature, a strain fecund at 24.5?C was obtained.
Caenorhabditis elegans is a species consisting almost entirely of hermaphro- ditic, self-fertilizing individuals (about one male out of 1000 hermaphrodites). Its fecundity is easy to measure when the nematodes are raised individually on a special agar medium (1). At 18?C, the strain Bergerac (2) studied shows an average fecundity of 141 offspring per hermaphrodite.
When an embryo grown at 18?C is transferred to growing conditions at
References and Notes
1. D. H. Copp, E. C. Cameron, B. A. Cheney, A. G. F. Davidson, K. G. Henze, Endocrinol- ogy 70, 638 (1962).
2. P. F. Hirsch, G. F. Gauthier, P. L. Munson, ibid. 73, 244 (1963).
3. P. F. Hirsch, E. F. Voelkel, P. L. Munson, Science 146, 412 (1964).
4. A. Baghdiantz, G. V. Foster, A. Edwards, M. A. Kumar, E. Slack, H. A. Soliman, I. MacIntyre, Nature 203, 1027 (1964).
5. A. Tenenhouse, C. Arnaud, H. Rasmussen, Proc. Nat. Acad. Sci. U.S. 53, 818 (1965).
6. L. G. Raisz, J. Clin. Invest. 44, 106 (1965). 7. A. D. Kenny and C. A. Heiskell, Fed. Proc.
24, 322 (1965). 8. M. A. Aliapoulios, A. Savery, P. L. Munson,
ibid., p. 322. 9. Supported by PHS grant AM 06205 and by
a Burroughs-Wellcome clinical pharmacology award. We thank William Y. W. Au for his invaluable help.
7 September 1965
Genetic Adaptation of Caenorhabditis elegans (Nematoda) to High Temperatures
Abstract. When taken directly from a strain kept for several years at 18?C in the laboratory, Caenorhabditis elegans cannot reproduce indefinitely at temper- atures higher than 22?C. By progressive and very slow increments of the breed- ing temperature, a strain fecund at 24.5?C was obtained.
Caenorhabditis elegans is a species consisting almost entirely of hermaphro- ditic, self-fertilizing individuals (about one male out of 1000 hermaphrodites). Its fecundity is easy to measure when the nematodes are raised individually on a special agar medium (1). At 18?C, the strain Bergerac (2) studied shows an average fecundity of 141 offspring per hermaphrodite.
When an embryo grown at 18?C is transferred to growing conditions at
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Generations
Fig. 1. Evolution of fecundity and sterility for successive generations of C. elegans after transfer from 18? to 22 ?C. Each point is the average of three experiments.
Generations
Fig. 1. Evolution of fecundity and sterility for successive generations of C. elegans after transfer from 18? to 22 ?C. Each point is the average of three experiments.
Generations
Fig. 1. Evolution of fecundity and sterility for successive generations of C. elegans after transfer from 18? to 22 ?C. Each point is the average of three experiments.
24.5 C, the embryo develops into a sterile adult whose morphology is ap- parently normal. When the growth con- ditions are changed from 18? to 23?C, the resulting adult has a very low fe- cundity. If the succeeding generations are kept at 23?C, fecundity decreases, and complete sterility is reached with the fifth or sixth generation. Thus there exists between normal (around 20?C) and immediately sterilizing (above 24?C) temperatures a range that leads to the extinction of the strain within a few generations.
When the nematodes were transferred from 18? to 22?C, fecundity dropped during the first few generations to a minimum and then gradually increased (Fig. 1). Hence it appears that a strain perfectly adapted to 22?C has been obtained.
Attempts to obtain a new strain at 23?C depend upon the time of transfer of the nematodes from 22? to 23?C. Transfers made up to approximately the 90th generation yielded results al- ready noted: fecundity decreased to zero over several generations. However, transfers made starting with the 95th generation showed fecundity that de- creased to a minimum and rose after- ward. Thus a strain, stable at 23 C, was obtained.
If animals that were stable at 23?C were transferred to 23.5?C, similar re- sults were obtained: adaptation to the new temperature occurred if the trans- fer was made within or after the 252nd generation.
Further, by successive increments of 0.5?C, a permanently fertile strain was finally obtained at 24.5?C (Fig. 2). This strain is radically different from the initial strain grown at 18?C, which, when directly transferred to 24.5 C, becomes immediately and irreversibly sterile.
Cytological study of gametogenesis showed that sterility of the nematodes transferred to high temperature came from an abnormal oogenesis similar to that produced by thermal shocks (3). Hence, the adapted animals had under- gone a change of ovarian physiology that permitted normal gametogenesis.
The gradual changes in fecundity and the apparently repetitive process at each stage of adaptation suggest that the cor- responding genetic modifications occur
24.5 C, the embryo develops into a sterile adult whose morphology is ap- parently normal. When the growth con- ditions are changed from 18? to 23?C, the resulting adult has a very low fe- cundity. If the succeeding generations are kept at 23?C, fecundity decreases, and complete sterility is reached with the fifth or sixth generation. Thus there exists between normal (around 20?C) and immediately sterilizing (above 24?C) temperatures a range that leads to the extinction of the strain within a few generations.
When the nematodes were transferred from 18? to 22?C, fecundity dropped during the first few generations to a minimum and then gradually increased (Fig. 1). Hence it appears that a strain perfectly adapted to 22?C has been obtained.
Attempts to obtain a new strain at 23?C depend upon the time of transfer of the nematodes from 22? to 23?C. Transfers made up to approximately the 90th generation yielded results al- ready noted: fecundity decreased to zero over several generations. However, transfers made starting with the 95th generation showed fecundity that de- creased to a minimum and rose after- ward. Thus a strain, stable at 23 C, was obtained.
If animals that were stable at 23?C were transferred to 23.5?C, similar re- sults were obtained: adaptation to the new temperature occurred if the trans- fer was made within or after the 252nd generation.
Further, by successive increments of 0.5?C, a permanently fertile strain was finally obtained at 24.5?C (Fig. 2). This strain is radically different from the initial strain grown at 18?C, which, when directly transferred to 24.5 C, becomes immediately and irreversibly sterile.
Cytological study of gametogenesis showed that sterility of the nematodes transferred to high temperature came from an abnormal oogenesis similar to that produced by thermal shocks (3). Hence, the adapted animals had under- gone a change of ovarian physiology that permitted normal gametogenesis.
The gradual changes in fecundity and the apparently repetitive process at each stage of adaptation suggest that the cor- responding genetic modifications occur
24.5 C, the embryo develops into a sterile adult whose morphology is ap- parently normal. When the growth con- ditions are changed from 18? to 23?C, the resulting adult has a very low fe- cundity. If the succeeding generations are kept at 23?C, fecundity decreases, and complete sterility is reached with the fifth or sixth generation. Thus there exists between normal (around 20?C) and immediately sterilizing (above 24?C) temperatures a range that leads to the extinction of the strain within a few generations.
When the nematodes were transferred from 18? to 22?C, fecundity dropped during the first few generations to a minimum and then gradually increased (Fig. 1). Hence it appears that a strain perfectly adapted to 22?C has been obtained.
Attempts to obtain a new strain at 23?C depend upon the time of transfer of the nematodes from 22? to 23?C. Transfers made up to approximately the 90th generation yielded results al- ready noted: fecundity decreased to zero over several generations. However, transfers made starting with the 95th generation showed fecundity that de- creased to a minimum and rose after- ward. Thus a strain, stable at 23 C, was obtained.
If animals that were stable at 23?C were transferred to 23.5?C, similar re- sults were obtained: adaptation to the new temperature occurred if the trans- fer was made within or after the 252nd generation.
Further, by successive increments of 0.5?C, a permanently fertile strain was finally obtained at 24.5?C (Fig. 2). This strain is radically different from the initial strain grown at 18?C, which, when directly transferred to 24.5 C, becomes immediately and irreversibly sterile.
Cytological study of gametogenesis showed that sterility of the nematodes transferred to high temperature came from an abnormal oogenesis similar to that produced by thermal shocks (3). Hence, the adapted animals had under- gone a change of ovarian physiology that permitted normal gametogenesis.
The gradual changes in fecundity and the apparently repetitive process at each stage of adaptation suggest that the cor- responding genetic modifications occur in successive steps of small degree over the generations studied. Since C. elegans is self-fertilizing, selection in a highly heterozygous state presumably cannot be exploited to achieve a progressive adaptation. Comprehensive observations
in successive steps of small degree over the generations studied. Since C. elegans is self-fertilizing, selection in a highly heterozygous state presumably cannot be exploited to achieve a progressive adaptation. Comprehensive observations
in successive steps of small degree over the generations studied. Since C. elegans is self-fertilizing, selection in a highly heterozygous state presumably cannot be exploited to achieve a progressive adaptation. Comprehensive observations
40 * ' 40 E
35 .' 35
S> 30 / \ ' 30
3 25 \ 25
U, r \o
for Vsucceive ge ra s of C. e s 15
after transfer from 24 to 24 .5
01 G2 G3 G4 G5 G7 G8 Gg Glo Gll G12 G13 Genierations
Fig. 2. Evolution of fecundity and sterility for successive generations of C. elegans after transfer from 24? to 24.5 ?C.
(4) support the assumption that adap- tive transmissible cytoplasmic states are produced gradually and are responsible for the production of fertile high-tem- perature strains.
J. BRUN Laboratoire de Zoologie experimentale, Faculte des Sciences, Universite de Lyon, France
References and Notes
1. V. Nigon, Ann. Sci. Nat. Zool., ser. 11, 11, 1 (1949).
2. H. V. Fatt and E. C. Dougherty, Science 141, 266 (1963).
3. J. Brun, Biol. Bull. 89, 326 (1955). 4. - , Ann. Biol. Animale. Biochim. Biophys.,
in press. 5. I thank Prof. V. Nigon for guidance during
this investigation and Dr. E. C. Dougherty for help with the manuscript.
29 September 1965
Antibodies in Gastric Juice
Abstract. The presence in gastric juice of specific antibody has been dem- onstrated. It is mainly an IgG antibody reacting with the cytoplasm of gastric cells; it has been detected in patients with atrophic gastritis, with or without pernicious anemia, whose serums con- tain antibodies to parietal-cell cyto- plasm. Evidence is presented that asso- ciated circulating antibody to cytoplasm of thyroid acinar cell does not appear in the gastric juice.
There is a growing body of evidence that, in man, immunoglobulins are normal components of various secre-
40 * ' 40 E
35 .' 35
S> 30 / \ ' 30
3 25 \ 25
U, r \o
for Vsucceive ge ra s of C. e s 15
after transfer from 24 to 24 .5
01 G2 G3 G4 G5 G7 G8 Gg Glo Gll G12 G13 Genierations
Fig. 2. Evolution of fecundity and sterility for successive generations of C. elegans after transfer from 24? to 24.5 ?C.
(4) support the assumption that adap- tive transmissible cytoplasmic states are produced gradually and are responsible for the production of fertile high-tem- perature strains.
J. BRUN Laboratoire de Zoologie experimentale, Faculte des Sciences, Universite de Lyon, France
References and Notes
1. V. Nigon, Ann. Sci. Nat. Zool., ser. 11, 11, 1 (1949).
2. H. V. Fatt and E. C. Dougherty, Science 141, 266 (1963).
3. J. Brun, Biol. Bull. 89, 326 (1955). 4. - , Ann. Biol. Animale. Biochim. Biophys.,
in press. 5. I thank Prof. V. Nigon for guidance during
this investigation and Dr. E. C. Dougherty for help with the manuscript.
29 September 1965
Antibodies in Gastric Juice
Abstract. The presence in gastric juice of specific antibody has been dem- onstrated. It is mainly an IgG antibody reacting with the cytoplasm of gastric cells; it has been detected in patients with atrophic gastritis, with or without pernicious anemia, whose serums con- tain antibodies to parietal-cell cyto- plasm. Evidence is presented that asso- ciated circulating antibody to cytoplasm of thyroid acinar cell does not appear in the gastric juice.
There is a growing body of evidence that, in man, immunoglobulins are normal components of various secre-
40 * ' 40 E
35 .' 35
S> 30 / \ ' 30
3 25 \ 25
U, r \o
for Vsucceive ge ra s of C. e s 15
after transfer from 24 to 24 .5
01 G2 G3 G4 G5 G7 G8 Gg Glo Gll G12 G13 Genierations
Fig. 2. Evolution of fecundity and sterility for successive generations of C. elegans after transfer from 24? to 24.5 ?C.
(4) support the assumption that adap- tive transmissible cytoplasmic states are produced gradually and are responsible for the production of fertile high-tem- perature strains.
J. BRUN Laboratoire de Zoologie experimentale, Faculte des Sciences, Universite de Lyon, France
References and Notes
1. V. Nigon, Ann. Sci. Nat. Zool., ser. 11, 11, 1 (1949).
2. H. V. Fatt and E. C. Dougherty, Science 141, 266 (1963).
3. J. Brun, Biol. Bull. 89, 326 (1955). 4. - , Ann. Biol. Animale. Biochim. Biophys.,
in press. 5. I thank Prof. V. Nigon for guidance during
this investigation and Dr. E. C. Dougherty for help with the manuscript.
29 September 1965
Antibodies in Gastric Juice
Abstract. The presence in gastric juice of specific antibody has been dem- onstrated. It is mainly an IgG antibody reacting with the cytoplasm of gastric cells; it has been detected in patients with atrophic gastritis, with or without pernicious anemia, whose serums con- tain antibodies to parietal-cell cyto- plasm. Evidence is presented that asso- ciated circulating antibody to cytoplasm of thyroid acinar cell does not appear in the gastric juice.
There is a growing body of evidence that, in man, immunoglobulins are normal components of various secre- tions, such as tears, saliva, colostrum tions, such as tears, saliva, colostrum tions, such as tears, saliva, colostrum
10 DECEMBER 1965 10 DECEMBER 1965 10 DECEMBER 1965 1467 1467 1467